Aw: Re: [tpmdd-devel] [PATCH v9 8/8] tpm: TPM 2.0 FIFO Interface

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Am Donnerstag, 4. Dezember 2014, 06:55:18 schrieb Jarkko Sakkinen:

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From: Will Arthur <redacted>

Detect TPM 2.0 by using the extended STS (STS3) register. For TPM 2.0,
instead of calling tpm_get_timeouts(), assign duration and timeout
values defined in the TPM 2.0 PTP specification.

Signed-off-by: Will Arthur <redacted>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

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+ sts3 = ioread8(chip->vendor.iobase + TPM_STS3(1));
+ if ((sts3 & TPM_STS3_TPM2_FAM) == TPM_STS3_TPM2_FAM)
+ chip->flags = TPM_CHIP_FLAG_TPM2;
+

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When loading tpm_tis force=1 with my tpm1.2 chip on a machine without bios
integration, it fets detected as a TPM2.0 chip :/

sudo rmmod tpm_tis
# modprobe tpm_tis force=1
modprobe: ERROR: could not insert 'tpm_tis': No such device
# dmesg
[ 263.903828] tpm_tis tpm_tis: 2.0 TPM (device-id 0xB, rev-id 16)
[ 263.948049] tpm_tis tpm_tis: A TPM error (10) occurred continue selftest
[ 263.948120] tpm_tis tpm_tis: TPM self test failed


sts3 is reported as 0xff from my TPM1.2

Hmm,
my TPM2.0 chip also reports sts3 as 0xff (when loading with force=1 on a
machine without bios integration)

[ 307.095344] sts3 ff
[ 307.095366] tpm_tis tpm_tis: 2.0 TPM (device-id 0x1A, rev-id 16)
[ 307.140047] tpm_tis tpm_tis: A TPM error (256) occurred continue selftest
[ 307.140056] tpm_tis tpm_tis: TPM self test failed

You are reading "sts3" - before requesting the locality and thus it returns 0xff for a TPM20 chip as well.
--> You have to have an active locality first.


For a TPM2.0 0xFF is not a valid value (if active locality is set), since reading commandCancel and resetEstablishment bit always return 0 on reads (according to spec).

--> 0xFF should be treated as a TPM1.2 (older tpms with TIS 1.2)
--> 0x04 should be treated as TPM 2.0
--> 0x08 should be treated as TPM1.2 (newer tpms with TIS1.3 enhanced)



Thanks,
Peter